In this ninth part of our mini-series on climate science, we turn to one of the key suspects in extreme weather events we have experienced in recent years—the shifting shape of the North Atlantic jet stream. And the fingerprints of the changing jet stream can be found in tree ring data. The guest in this episode has studied three centuries of European tree rings and found that the shape of the jet stream, along with clear deviations from historical weather, began in the 1960s, pointing to a connection to the changing climate. Other researchers have come to similar conclusions by studying things like the difference between Arctic and mid-latitude temperatures over time. And they conclude that increases in greenhouse gas emissions will make the jet stream increasingly wavy in the future, exacerbating such extreme weather events.
Valerie Trouet received her PhD in Bioscience Engineering at the KULeuven (Belgium) in 2004. After a post-doctoral research position in the Geography Department at the Pennsylvania State University (2005-2006), she worked as a research scientist at the Swiss Federal Research Institute WSL (2007-2010). At the time of this 2018 interview she was an Associate Professor at the Laboratory of Tree-Ring Research at the University of Arizona, leading the Spatiotemporal Interactions between Climate and Ecosystems research group.
She is now a professor at the Laboratory of Tree-Ring Research, with a joint appointment in the Department of Hydrology and Atmospheric Sciences, and from 2026 is also affiliated with the Department of Water and Climate at the Vrije Universiteit Brussel. In 2023 and 2024 she served as founding Scientific Director of the Belgian Climate Centre. The broad-audience book she was writing at the time of this interview was published in 2020 as Tree Story: The History of the World Written in Rings (Johns Hopkins University Press). In 2026 she was named a Fellow of the American Association for the Advancement of Science.
On the Web: valerietrouet.com
Recording date: February 20, 2018
Air date: March 21, 2018
Geek rating: 3